Stabilized lubricants



'eration in modern eng'ines.

Patented May 1, 1945,

STABILIZED LUBRICANTS Norman D. Williams, Chicago, and William J.

Backofl, Elmliurst, Ill

., assignors to The Pure Oil Company, Chicago, 11]., a corporation of Ohio No Drawing.

Application December 23, 1944, Serial No. 569,628

9 Claims. 101.252.4211) I This application is a continuation-in-part of our copending application Serial No. 424,792, nled December 29, 1941, entitled Stabilized lubricants.

This invention relates to lubricating oils and more particularly to lubricating oil compositions containing oil soluble improving agent or agents effective to'retard deterioration of lubricants and to inhibit or mitigate the normal corrosive action of lubricating oil or the deterioration productsthereof upon metals, particularly bearingmetals, under conditions of use, such improving agents also having the properties of increasing "oiliness as well as-imparting extreme pressure characteristics and depressing the pour test of mineral lubricating oils.

Although many technological advances have,

been made in the art of refining and applying lubricating oils and in the composition of bearing materials, modern lubricating oils and bearings often fail to perform satisfactorily. It is well known in the art that straight petroleum lubricants have fairly well defined limits of bearing speeds, pressures and temperatures within which they will give acceptable service. limitations are often exceeded in modem engineering design, resulting in machines that cannot be satisfactorilylubricated by'straight mineral oils. When the aforementioned limitations are exceeded, the rate of deterioration of the lubrieating oils is materially increased resulting in oxidation products of a troublesome nature. Some of these oxidation products, such as highly re ous insoluble bodies, known as insoluble sludge, deposit in the hot portions of the engine thereby causing faulty ring action as well as causing bearing failures by depositing in the ducts of small diameter through which the oil normally flows to the bearings. These modern designs are justified by engineers in their efforts to provide machines to conform to the ever-increasing demand for compactness, speed, power and accelmodern machines have already exceeded the above-mentioned limits wherein straight petroleum lubrieating-oils perform acceptably; therefore, it is These necessary to provide lubricating compositions that extend and widen the limits formerly associated with straight lubricating oils.

Moreover, highly paraflinic oils having excellent viscosity-gravity constants, volatilities, -car-' bon residue values, and resistance to sludging and oxidationand hence of high value for use under relatively mild lubricating conditions, sometimes tend to be even less satisfactory than the less highly parafilnic oils, when the ordinary limits of temperature, pressure; and bearing speed are exceeded. This may be due in part to the fact that the deterioration products of paraflinic constituents are more active than those resulting from naphthenic or other non-parafllnic constituents, and it may be due also to the fact that the non-paraflinic constituents have some inhibiting effect upon either the deterioration of the paraflinic constituents or upon the behavior of products resulting from such deterioration, at

high temperatures and pressures, and in the presenee of certain metals. However, the inhibiting value of the non-parafllnic constituents is low per unit concentratiomand they are less satisfactory with respect to viscosity-gravity constant, carbon residue, and similar criteria of lubricating quality than the paraflinic constituents. A desirable solution of the problem would be to substitute for the non-parafiinic constituents removed in the more drastic refining treatments or absent because of the highly'parafiinic nature of the original stock, some inhibiting or mitigatingagent which would be far more effective per unit concentration and hence less detrimental with respect tothe other physical properties which also. effect the ultimate lubricating value I of the 011.

Improved bearing metals have recently been developed which are mechanically advantageous under many operating conditions. These bearing metals include binary and ternary alloys of cadmium, silver, copper, lead and nickel, as examples of such improved bearing metals frequently-employed atthe'present time may be mentioned cadmium-silver, cadmium-silver-copper, cadmium-nickel-copper, and copper-lead alloys. However, such alloys are more subject to chemical attack than babbitt and other bearing alloys used in the past, and their use at high temperatures, high speeds and high pressures is sometimes accompanied by a deterioration of the oils employed for their lubrication, which in turn may destroy the bearings. The exact mechanism ofthis action is complicated and is perhaps not fully understood; it is quite possible that some of the metals present in the bearings tend to promote such deterioration, and that other metals )1 the same metal, are subjectto attack from the deterioration products. Whatever the cause oils may be so improved as to give satisfactory operating results under the conditions noted, and this is especially true insofar as concerns the more highly parafilnic oils, which should and do command a premium in price. Moreover, it is well known that all hydrocarbon oils are more or less subject to changes through oxidation resulting in undesirable deterioration, acid formation, and increase in carbon residue, viscosity, sludging and the like. Such oxidation changes may become more rapid or more far-reaching in extent in the presence of metals such as those employed in modern bearings, for example, those of the general class mentioned above.

In order to meet these problems and to provide more satisfactory lubrication under the conditions indicated, various improvement agents have been incorporated in hydrocarbon oils prior to, their sale and use. A primary requisite of such agents is good oil-solubility under service and marketing conditions and since solubilities vary in different types of oils, the improvement agent should be soluble'in the requisite amount in oils of different types.

It is an object of this invention to provide a reductions in the corrosive tendency and oxidation deterioration, as indicated by sludge 0r varnish formation, in mineral lubricating oils. Fatty bodies which fall within classes;IV, VII, VIII, IX, X and XII of the table entitled Constants of vegetable and animal oils, fats and waxes," found on page 862 of the Handbook of Chemistry and are neutral fats, which are known to consist substantially entirely of neutral esters in contrast to those fatty bodies which contain high proportions of fatty acids. While the neutral fats have been found to produce additiveagents having unusually effective properties, the most uniformly superior results have been obtained with those additives prepared from wool grease.

Generally speaking, the phosphorus sulfide treated fatty bodies may be saponified with any oneor more of a wide variety of metal compounds. However, the saponification products resulting from the use of metals of group 2 of the periodic table are superior additives, particularly from the metals calcium, strontium, barium and magnesium. Tin and lead soaps are also highly emcacious.

Phosphorus sesquisulfide. P483, has been found to be the most'suitable phosphorus sulfide, al-

though any other phosphorus sulfide such as phosphorus pentasulfide, P235, may be employed.

novel improving agent for lubricating composi- 4 tions.

It is another object of this invention to provide a lubricating oil suitable for use in internal combustionengines which oil is inhibited against oxidation deterioration, varnish formation and bearing corrosion.

It is a further object of this invention to provide multi-functional mineral lubricating oil additive agents which have the property of inhibit- The unusual results obtained by the use of additives within the scope of this invention are gen- .erally attributed to the particular chemical structure of the additives, which structure may only be obtained by the use of phosphorus sulfides.

As a result of much investigation, it has been definitely established that fatty bodies which have been separately reacted with sulfur and/or phosphorus compounds thereof, other than phosphorus sulfide, are not the equivalent of the materials herein described and which are obtained by chemically reacting fatty bodies with phosphorus sulfide.

The metal soaps of the invention are preferably prepared by contacting an appropriate phosphorus sulfide such as phosphorus sesquisulfide, with fatty body at temperatures of the order of 150 to 400 F. followed by saponification of the phosphorized. fatty body with a suitable metal compound such as an oxide or hydroxide, al-

' though additives having considerable merit may It has now been found that improving agents for lubricating compositions, particularly mineral lubricating oils which have the property of inbe prepared by first saponifying the fatty body with the metal compound and the metal soap subsequently reacted with phosphorus sulfide. The saponification may be readily carried out at relatively low elevated temperatures such as invention, a fatty bodysuch as wool grease is heated sufllciently to make the wool grease quite fluid (about 160 F.) and a suitable phosphorus su-lflde such as phosphorus sesquisulfide, P483,

added with continuous agitation. The temperature is slowly increased to approximately 220 F.

' and maintained at this temperature with contincopper strip corrosion tests which are satisfac- 20 indication of a satisfactory completion of the re- 80 uous agitation until the P453 is completely reacted with the wool grease as indicated by a copper strip corrosion test. The copper strip corrosion test is conducted by immersing a polished copper strip in the reaction mixture at reaction temperature for three minutes. A peacock or irridescent strip is considered satisfactory whereas a black or gray strip is not satisfactory. In

making the corrosion test caution should be exercised to mak sure that the reactants have passed through the stage at which a gray or black copper strip is obtained since in some instances tory are obtained for very short periods such as within about fifteen minutes, subsequent to the mixing of fatty body and phosphorus sulfide. Such corrosion tests do not indicate completion of the reaction of the phosphorus compound and further heating is necessary" during which time black or gray copper strip corrosion tests will beobtained and subsequently the aforementioned peacock colored strip is obtained which is an action. The reaction mixture is preferably not allowed to exceed 240 F. temperature until the exothermic heat of reaction is substantially complete. Phospliorized fatty bodies in which the temperature exceeds about 240 F. prior to com- 85 pletion of the exothermic heat of reaction are not uniform in quality and in general show a much lower content of chemically combined phosphorus and sulfur for a, given amount of phosphorus sulfide employed in the reaction mix- 40 ture. After the exothermic heat of reaction has subsided, the reaction temperature may be carried to temperatures of the order of 300 F. or even 400 F., although temperatures of 215 to 240 F. have been found to produce most uniform results. l

The time required for effecting satisfactory chemical reaction between the phosphorus sulfide and fatty body will vary considerably depending upon such factors as reaction temperature, the particular fatty body employed, the

hours are generally required to complete the re- 00 action without air blowing.

As a specific example (1), '1900 parts by weight of wool grease having the following propertiessaponification No. to iodine No. 41 to 46;

fi l value 29 to 41, was heated to a tempera- 65 ture of approximately F. and 100 parts by weight of commercial grade phosphorus sesquisulflde, Piss. slowly added with continuous agita 'tion. The temperaturewas gradually increased to 220 to 230 F. and maintained at this tem- I0 perature until a satisfactory copper strip corrosion test was obtained. This required a period of six hours. The phosphorized wool grease was ill-- tered to remove small amounts of solid impurities It has been found that if air is blown M 3 to contain 1.68%su1 furand 2.3%" phosphorus.

One part by weight of the phosphorized wool grease was mixed with 2 parts by weight of 180 viscosity at 100 Pennsylvania neutral oil and the mixture brought to a temperature of .225 to 235 F. 0.185 part by weight of crystalline barium hydroxide, Ba(0H) 2.8H20; was slowly added with continuous agitation. A considerable amount of frothing occurred due to evolution of steam. The mixture was maintained at the aforementioned temperature until all frothing had ceased and heating was continued for approximately /z hour thereafter to make certain that the saponification reaction had terminated. The time required for reaction of the barium hydroxide was one hour. The saponified product was filtered to remove small amounts of solid by-product materials thereby. producing a. homogeneous, light brown product. Analysis of the filtered material showed that it contained in combined form, 2.7% barium,

0.55% phosphorus and 0.34% sulfur. The theoretical content of these materials based on the amounts of reactants employed is 2.6% barium, 0.74% phosphorus and 0.54% sulfur. The filtered saponified concentrate was a light colored, slight- 1y viscous liquid having a Saybolt viscosity at 100 F. of 457 seconds.

In another example (2) 1500 grams of wool grease and 80 grams of phosphorussesquisulfide were mixed together and the mixture heated to 230 F. while being constantly stirred." After the reaction mixture had attained a temperature of 230 F. heating was discontinued and air was blown through the mixture at the rate of 45 cubic feet per hour for a period of one hour. The mixture was continuously stirred during the entire time. The rate of air blowing was sufficient to maintain the reaction mixture at 230 F. without application of heat. At the end of the one hour blowing period the reaction was complete, as evidenced by the stoppage of fuming andthe failure to obtain a temperature increase with an increase in rate of air fiow.

The reaction mixture was then filtered at 230 in an amount equal to .09 parts by weight of barium. The mixture was slowly heated to a temperature of 225 to 235 F. with continuous agitation in order to saponify the reaction prodnot in the same manner as described in Example 1. After saponification was complete heating was continued at a temperature .of approximately 340 F. for a period of 45 minutes in order to insure completion of the saponification reaction and to stabilize the product. The resulting saponifled product showed the following analysis Per cent bariumby weight 2.62 Per cent sulfur by weight 0.41 Per cent phosphorus by weight 0.64

In another example (3), sperm oil was phosphorized with phosphorus sesquisulfide with air blowing in the same manner as described with reference to, wool grease in Example 2. Separate portions of the phosphorized sperm oil reaction product were saponified with zinc and barium and upon analysis the filtered gm was found, 3 hydroxides in the manner heretofore described,

so that resulting saponifled product contained 2.8% of the metal.

This concentrate of barium soap of phosphorized wool grease dissolved in neutral oil is readily soluble in mineral oil and is easily incorporated in lubricating compositions, particularly mineral lubricating oils, in widely varying proportions depending uponthe particular service to which the oil is to be put and the composition of the soap. Generally speaking, that amount of soap is employed which will produce lubricant compositions containing from about 0.005% to .5% by weight of metal, although larger amounts such as 1% by weight of metal, are satisfactory. In incorporating soaps of the invention into crank case oils used in internal combustion engines, consideration must be given to the matter of thickening of the oil when large proportions are employed. Excessive viscosity increase must be avoided. In specific examples, approximate- 1y 3.1% by weight of barium soap additives increased the Saybolt viscosity of a sample of Pennsylvania S. A. E. motor oil from 190 to 201 at 100 Rand increased a sample of S. A. E.

to as much as 10% based on the fatty material employed. Ordinarily, best results are obtained when approximately 1.5% to 4% of phosphorus in the form of phosphorus sulfide is used in th phosphorizing step.

In order to demonstrate the ability of metal soaps of phosphorized fatty bodies for inhibiting bearing corrosion, mineral oil blends containin varying proportions of soaps prepared in accordance with Example 1 were subjected to Under.- wood corrosion'tests. This test was chosen inasmuch as experience with various corrosion tests has indicated that the Underwood machine test results correlate actual service results very closely. The Underwood test is described in an article entitled, Automotive bearing material and their application, by A. F. Underwood, Journal of Society of Automotive Engineers, vol. 43, pages 385 to 392, September 1938. A series of such tests was run on 180 viscosity at 100 Pennsylvania neu- 'traloil and on separate samples of the same oil to which was added various amounts of a number bodies. These results are shown in Table I.

TABLE I Underwood tests lllhos- P t Additive Sludge P cell Ag-Cd OuPb Phos' besrin bearin H N z plo Metal pound phorus Per cent Fatty body 8 8 No. reacted eom- 3; hosg ig g No F i g g ffi with fatty pound metal l orized n50 so u u Ody at per cent per cent per cent 3 1 0. 058 3 WooLgrease- 0. 0025 0. 0905 10 1. 04 50 36 1. 50 3, 1 0. 035 3 (100 .00 0.0619 10 0.81 19 2. 5 0. 121 3 Sperm 011 0.0104 0. 0165 10 B0 03 .31 79 7 0.121 3 .d0 0.0034 0.0042 10 .84 .03 .43 .73 i 10 0. 121 3 Wool grease 0. 0072 0.0255 10 .81 .39 15 .80 1 0.5 0. 121 3 d0 0.0099 0.1141 10 .60 .76 .11 .40 10 0.121 3 ..do 0. 5700 0.1724 5 4.30 .74 3.64 20 0. 121 8 do 0.3570 0.2134 5 5. 0. 121 3.5 do 0. 0020 0.0%7 10 1.40' .44 .26 .47 7 0.06 1.75 .....do 0.000 0350 10 1.30 .49 .20 .59

1 Equivalent to 0.1217 barium. 1 Equivalent in phosphorus content to 5% P481.

tions of the oil to combustion conditions in the combustion chamber.

In saponifying the phosphorized fatty bodies with metal compounds, it is preferred to use proportions of the metal compound which are insufiicient to completely saponify the phosphorlzed fatty body, since superior result are obtained with those compositions in which a substantial amount of unsaponified or unsaponiflable phosphorized fatty body is present. No satisfactory explanation of this phenomenon has been found. Most satisfactory results have been obtained when approximately to /4 of the saponiflable content of the original fat, as determined by the A. S. T. M. procedure for saponiflcation number, is reacted with metallic compound to form the metal soap.

Particularly satisfactory metallic soaps are prepared from phosphorized fatty bodies which are phosphorized with phosphorus sulfides in amounts ranging from 0.3% to 5% by weight of A set of samples similar to those employed in the. Underwood tests was prepared and tested for detergency and anti-oxidant properties under actual conditions of use in an internal combustion engine. These tests were carried out in Lauson engines and are known as Lauson varnish tests. In these tests the oil with or without additive is used as a crank case oil in a single cylinder Lauson engine operated under the following conditions: Duration of test-25 hours; speed-1600 R. P. M.; load-1 kw: jacket temperature- F.; oil sump temperature-280 1 to 5 which was established from the results of inspections of many pistons previously run under identical engine conditions using different grades of lubricants whereby to obtain pistons of flve different degrees of cleanliness. The degree of cleanliness is arrived at by inspecting the amount of deposition on the piston rings, ring lands, pisphosphorus based'on the fatty body. although ton skirt and under side of the piston. "According to the scale, a piston rating of 1 is the. poorest rating assigned, while a piston rating of 5 is the the piston ratings obtained on the same 180 viscosity at 100 Pennsylvania neutral oil, as well as separate samples of the same oil containing varying amounts of additives prepared in accordance with this invention. 1

crucible without suction for a few minutes before each portion of the chloroform isdrawn through the crucible.) I

The residue'is then dried in an for 30 minutes, cooled and weighed. The loss in weightvis chloroform soluble.

TABLE II Lauson varnish test Pb h Additive osp orus v t Sam is com and Piston No? mail with 33353 353 Per cent Per cent ratios fatty body metal phospgitonzed l Straight oil 1 2 Strontium 7.- 0.154 3 4 7 0.042 3 5 7 0.070 s d 4 7 0.121 3 Tallow 3 7 0.121 3- 'Menha den oil-.. 5+ 7 0. 121 3 Corn 011 3 7 o. 121 3 Boys been 00.... 3+ 9... 7 0.242 1. 4+ 10. 7 0. 121 0. 4 11 7 0.680 3 6+ 12. 1 0. 121 3 3 13 l 6. 4 0. 121 3 3+ 14. 10 0. 121 3 15 7 0.121 3 5+ is 5 0.060 a 4 17 1 v 0.242 3 5+ 1 Equivalent in phosphorus content to 6% phosphorus sesquisulfide.

In both Tables I and II the Percent phosphorus compound heading shows the amount of phosphorus compound, based in the fatty body employed, thattwas reacted with the fatty body. The Percent metal and Percent phosphorized fat headings indicate the respective amounts of ,insoluble The "naphtha insoluble, chloroform soluble and soluble sludge are determined as follows: Naphtiuz insoluble (insoluble sludge) Three grams of the oil is mixed in an Erlenmeyer flask with 100 cc. of A. S. T. M. precipitation naphtha, of the type specified in A. S. T. M. method D91-35. The oil and naphtha are -thoroughly mixed. and allowed to stand for three hours. The insoluble matter is then filtered through a tared Gooch porcelain crucible, previously prepared with an asbestos pad 1" thick and dried in an oven at 300 F. for 30 minutes. The insoluble residue is washed with 100 cc. A. S. T. M. naphtha and dried in an oven at 300 F. for thirty minutes, cooled and weighed.

The increase in weight is naphtha insoluble.

chloroform soluble The chloroform soluble is extracted from the dried and weighed naphtha insoluble residue by pouring successive portions of chloroform through the filter pad using light suction. 100 cc. of chloroform is generally sufiicient but the extraction should be continued until the filtrate is colorless. (With heavy fnaphtha insoluble" residues the chloroform is allowed to stand in the The solubility in chloroform of the residue from the (naphtha insoluble" determination is affected by the time and temperature of drying. For this reason, in order to secure check results in the chloroform soluble determination, the drying time and temperature, especially in the naphtha determination, should be carefully controlled. I

It usually happens that in the Underwood test there is no particular difficulty in filtering, regardless of whether the oils contain detergents or not. However, when these methodsare applied to used'crankcase oils it sometimes happens that oils whichcontain detergents will not give a clear filtrate. Under these conditions, the filtrate is refiltered through a second Gooch filter and' the deposits from both crucibles added in reporting naphtha insoluble (and chloroform soluble).

Propane insoluble (soluble sludge) The filtrate from the naphtha insoluble is concentrated to 20 cc. by evaporation and is transferred quantitatively to the extraction apparatus described in Industrial and Engineering Chemistry, April 15, 1939, page 183. The remaining naphtha is now completely removed from'the oil sample by evaporation on a steam bath. The propane extraction is carried out as directed in the above-mentioned article. The propane insoluble material remaining is calculated in percentage and reported as soluble sludge.

From the data shown in Table I, it will be seen that the bearing corrosion and sludging tendency of the straight oil has been materially reduced by the incorporation of suitable additives. The

silver-cadmium bearing corrosion loss with the,

straight Pennsylvania neutral oil amounted to over 1.5 grams, whereas the losses obtained under the same test conditions when using separate, samples of the same oil containing approximately 3% of the preferred type of additive compound in which the fat was treated with phos-' phorus sulfide, were of the-order of 0.01 gram or less, most of the lossesbeing'below 0.007 gram. A similar improvement in the reduction of the copper-lead bearing losses is also shown; Furoven at 300 F.

thermore, the sludge formation in the oil and development of acidity is greatly reduced by incorporation of the additives as shown by the neutralization number and sludge tests. It will be further noted from the data in this table that the soaps prepared from wool grease which had been phosphorized with phosphorus compounds other thana phosphorus sulfide, produced materially higher bearing losses than those soap's prepared from phosphorized wool grease in which thephosphorizing was effected by means of phosphorus sulfides and that the best results were obtained when phosphorus sesquisulfide was used l was obtained onlyby the use of an aluminum piston, since when using the usual cast-iron piston the oil deteriorated so rapidly that it was not possible to complete a test run of 25 hours. Separate samples of the same oil which contained approximately 3% or less of additives prepared in accordance with this invention, produced piston ratings materially above that of the straight oil, the ratings ranging from 3 to the latter being the highest ratins'obtainable on this scale. While all of the soaps of phosphorized fats shown in Table II materially improved the piston rat"- ing, as compared to the straight oil, it will be noted that the best ratings were obtained on ditional samples of the same neutral oil containing approximately 3% by weight of additives prepared by phosphorizing wool grease with 7% by weight of phosphorus sesquisulfide and reacting separate portions of phosphorized wool grease with hydrated-crystalline barium hydroxide and diphenyl tin oxide. The tin and barium soaps were incorporated in 180 viscosity Pennsylvania neutral oil'in such amounts as to produce the following composition:

' Per cent by weight Neutral oil 96.173 Barium soap.- 3.242 Tin soap 0.585

Based on the total composition, the barium soap contained. 0.242% by weight of barium and the tin soap 0.049% by weight of tin. The piston rating obtained from a test of this material was 5+, showing that such soaps are highly eflicacious for inhibiting the oxidation deterioration and ring sticking properties of mineral lubricating oils.

A further indication of the unusual properties of additives within the scope of this invention for improving the properties of mineral lubricating. oils,,may be obtained by comparing the Lauson varnish test and Underwood test data in Table III with tests of the preferred materials shown in Tables I and II. The data in Table III were obtained on separate samples of the same Pennsylvania neutral oil used to obtain the data in Table II and which contained similar amounts of barium soaps of fats which were sulfurized with elemental sulfur instead of being phosphorized with phosphorus sulfide- Data on soaps of sulfurized fats are shown in Table III.

- TABLI III Lauson varnish test Additive Per cent elemental Piston Sam 10 No. Kind of fat p Per cent Per cent metal treated fat 1 Straight il 0 0 1 a R m 0. 121 3 3 Underwood tests Additive Ag-Cd CuPb Per cent elemental Hours Sam is No. Fat 11; g

p Per cent gag loss loss metal at 0 1. 6779 0. 1733 10 0. 121 3 0. 6945 0. W16 10 0.121 3 .d0 0.2214 0. 1108 5 0. 121 3 Prime lard 011-... 0. M 0. 1040 6 tained on samples 6, 11 and 15, which were prepared from menhaden oil, lard oil and wool grease, respectively, all of which were phosphorized by reaction with phosphorus sesquisulfide; thus clearly showing the unusually superior properties of the preferred materials of this invention.

Lauson v The sulfurized fatty bodies used in these tests were sulfurized by reacting prime lard oil or wool grease with the indicated amounts of elementary sulfur at a temperature of approximately 325 F. until a satisfactory copper strip corrosion test was obtained. The sulfurized fat was then saponified with Ba(OH)2.8HzO in the manner previously described in, Example 1 in connection with the saponifleation of the phosphorus sulfide treated fats to produce the indicated amounts of arnish tests were also obtained on ,adbarium in the finished additive. It will be seen that soaps of the suliurized fatty bodies improved the piston rating over the straight oil in the Lauson varnish tests but that the'improvement was not nearly as great as when similar soaps of phosphorized, particularl phosporus sesquisulfide treated fats were incorporated in the mineral oil. Note particularly Examples .15 and 16 of Table H. The soaps of the phosphorus sesquesulfide treated fats gave piston ratings of whereas the soaps of the suliurized fats gave engine ratings from 2 W3. A similar contrast single cylinder Lauson engines that are employed in the Lauson varnish test. However, the Operating conditions are much more severe as may be seen from the following data showing the conditions maintained throughoutthe test:

- Gravity Flash 445 Fire 500 Saybolt viscosity at 100 F 525-585 Saybolt viscosity at 130 F 220-240 Saybolt viscosity at 210 F 60-62 Pour test-maximum Carbon residue per cent.. 3 N. P. A. color--maximum 7 Duration of test -hours 25 R. P. M., 1800; load.- kw 1 Jacket temperature F 400 Sump temperature F 225 Piston clearance inches... 0.007 Type piston Aluminum "The foregoing conditions have been found to closely approximate the conditions to which lubricating oils are subjected in modern high speed Diesel engines.

for overall cleanliness and a numerical merit ratin'g assigned, a number 1 rating for a ring indicating that the ring is stuck, whereas a number 5 rating for a ring indicates a sufficiently clean condition that when the piston is carefully moved from a vertical to horizontal position, the ring will fall into the ring groove under its own weight. The condition of the under side of the piston and the piston skirt are also carefully examined and similar numerical ratings assigned. From .an average of the numerical ratings an overall piston rating is obtained. Table IV shows the Lauson ring-sticking test results obtained on a standard grade of S. A. E. 30 motor oil containing barium soap additives prepared At the completion of the 25-. hour test period, the piston are removed, and each of the three piston rings carefully examined The S. A. E. 30 motor oil 'used in all of the above tests had the following specifications:

The barium soaps of phosphorus sesquisuli'lde treated wool grease shown in Examples 2 and 3 of Table IV'were prepared by the same method as previously described in Example 1. It will be seen from the data in Table IV that the oil without any additive deposited gum or varnish on the Lauson piston to such an extent to produce a piston rating of 2+. One of the compression rings was completely stuck as indicated by a rating of 1. When small amounts of barium soap of phosphorus sesquisulfide treated wool grease were added to the same motor oil, the overall piston ratings obtained were 4+. The individual piston ring ratings were either 4 or 5. This clearly showsthat under conditions of severe service, the barium soaps of phosphorus 'sesquisulfide treated fat such as wool grease are highly effective additives for improving mineral lubricating oils under conditions of severe service.

An indication of the pour depressing properties of metal soaps of phosphorized fatty bodies is given in TableV.

TABLE V Additive Phosphorized fatty body Per cent phos- Per cent Pour, phorize barium F. fatty body Wool grease reacted with 5% P48 3. 0 121 0 Do 1.75 0.06 -5' D0 0. 87 0. 06 +5 Blank .1. None +30 obtained on samples of the same 180 vis. Pennsylvania neutral oil that was employed in the tests shown in Tables I, II and III. The straight oil had a pour test of +30 F., whereas the oil containing 0.93% of the barium soap of phosphorus sesquisulfide treated wool grease had a pour test of +5 F., or *a reduction in.pour of 25 F. Similarly, when 1.81% of the same barium soap was incorporated in another sample of the same oil, the pour test was reduced to 5 F., or a reduction of 35 F.

from phosphorus sesquisuli'ide treated wool Further tests were made on a Lauson engine grease. with lubricating oils prepared in accordance with Teas: IV Lauson ring-sticking tests Piston ring ratings a??? ma a 3; can addi- 3 K 322:5; M piston Com- Com- 'sition tive mm 3%; gm

3121 2 W 1 2+ 4 i i oo grease. 11.242 5 -.do 4 6 s Jacket temperature F. 1'70 Sump temperature F 280 Load w 1.3 to 1.4 R. P. M 1600 Duration of tests hours- 25 The results of this test showed that the barium soaps of wool grease phosphorus sesquisulflde and of sperm oil phosphorus sesquisulfide were substantially the same when prepared either with or without the air-blowing. The zinc-sperm oilphosphorus sesquisulfide product did not give the over-all engine cleanliness of the other products, but the bearings showed less corrosion with the zinc sperm oil phosphorus sesquisulfide product than with the other products.

It will be seen, therefore, that the metal soaps of fatty bodies which have been reacted with phosphorus sulfide have unusual properties in imparting corrosion resisting properties, resistance 'to sludge and varnish formation and reducing the pour test as well as generally improving the oils with respect to their use in modern internal combustion engines.

While the invention has been described hereinabove with reference to various preferred forms, proportions and embodiments, and with reference to. various specific examples, it will be understood that the invention is not limited to the details of such illustrative embodiments or examples but may be practiced by various methods within the scope of the claims hereinafter made.

It is claimed: I

1. Method of preparing a lubricant additive which comprises reacting wool grease with phosphorus sesquisulfide, in an amount equivalerit to 1.5.to 4% by weight of phosphorus based on the wool grease, at a. temperature not exceeding 240 F. until the reaction product has good copper strip corrosion, then saponifying it with crystalline barium hydroxide in amount sufllcient to saponify at least of the wool grease-phosphorus s'esquisulfide reaction product but insufficient to completely saponify it.

2. A lubricating oil comprising a mineral 1ubricating oil and the soap formed by saponifying with hydrated barium hydroxide at least 50% of but not the entire saponifiable content of the product resulting from chemically reacting wool grease with phosphorus sesquisulfide in an amount equivalent to 1.5 to 4% of phosphorus based on the wool grease, at a temperature oi approximately 240 F. until the exothermic reaction has subsided and continuing the reaction at a temperature not in excess of 400 F. until the product gives a good copper strip test, the amount of soap in the lubricating oil being equivalent to 0.005 to 0.5% by weight of barium.

3. Method of preparing a lubricant additive which comprises reacting wool grease with phosphorus sesquisulfide, in an amount equivalent to 1.5 to 4% by weight of phosphorus based on the wool grease, at a temperature not exceeding 240 F. until the reaction product has good copper strip corrosion, then saponifying it with a compound selected from the group consisting of the oxide and hydroxide of zinc, barium, cal- "cium, strontium and magnesium in amount suf-' :fioient to saponify at least 50% of the wool grease-phosphorus sesquisulflde reaction product but 'insuflicient to completely saponify it.

4. A lubricating oil comprising a, mineral lubricating oil and the soap formed by saponifying with a compound selected from the group consisting of the oxide and hydroxide of zinc, barium, calcium, strontium and magnesium at least 50% of but not the entire saponifiable content of the product resulting from-chemically reacting wool grease with phosphorus sesquisulfide in an amount equivalent .to 1.5 to 4% ofphosphorus based on the wool grease, at a temperature of approximately 240 F. 'until the exothermic reaction has subsided and continuing the reaction at a temperature not in excess of 400 F. until the product gives a good copper strip test, the amount of soap in the lubricating oil being equivalent to 0.005 to 0.5% by weight of barium.

5. The method of preparing a lubricant additive which comprises reacting a substance selected-from the. group consisting of non-drying animal and vegetable oils, fats and waxes with a phosphorus sulfide in an amount equivalent to 1.5 to 4% by weight of phosphorus based on said substance at a temperature not exceeding 240 .F..until the reaction product has good copper strip corrosion, then saponii'ying it with a compound selected from the'group consisting of theoxides and hydroxides of zinc, barium, calcium, strontium and magnesium in amounts sufficient to saponify at le'ast50% of said reaction product but insufficient to completely saponify 6. A lubricant comprising a. soap formed by saponifying in thepresence of a mineral lubrieating oil by means of a compound of a metal selected from the group consisting of zinc, barium, calcium, strontium and magnesium, at least 50% but not the entire saponifiable content of the product resulting from chemically reacting a substance selected from the group consisting of non-drying animal and vegetable oils, fats and waxes with a phosphorus sulfide in an amount equivalent to 1.5 to 4% by weight of phosphorus, based on said substance, at a temperature of approximately 215-240 F. until the reaction product has a good copper strip corrosion.

'7. The method in accordance with claim 1 in which the reaction mixture is blown with air during the reaction period.

8. The method in accordance with claim 3 in which the reaction mixture is blown with air during the reaction period.

9. The method in accordance with claim 5 in which the reaction mixture is blown with air during the reaction period at a suflicient. rate to maintain the desired reaction temperature. 

